1. Field of the Invention
The present invention relates to novel amphoteric tricyclic compounds and pharmacologically acceptable salts thereof which have antihistaminic activity and antiallergic activity and are useful as medicaments for the treatment of bronchial asthma, allergic rhinitis, dermatosis, urticaria and the like.
The present invention also relates to a method for preparing the amphoteric tricyclic compound, a pharmaceutical composition useful for the treatment of allergic diseases and bronchial asthma which comprises an effective amount of the amphoteric tricyclic compound, and a method for treatment allergic diseases and bronchial asthma comprising the step of administering an effective amount of the amphoteric tricyclic compound to a patient.
2. Description of the Related Art
Several antihistaminic agents and antiallergic agents are known which are characterized to have tricyclic structures. Examples of tricyclic compounds having a pyridine nucleus include clinically available Azatadine (The Merck Index, 11th edition, 917) represented by the following formula: ##STR2## and Loratadine (The Merck Index, 11th edition, 5455) represented by the following formula. ##STR3##
Furthermore, as compounds useful for the treatment of allergic diseases, WO89/10369 discloses, for example, the compounds represented by the following formula: ##STR4## and WO88/3138 discloses, for example, the compounds represented by the following formula. ##STR5##
All of these compounds are characterized as being basic type compounds. Tricyclic compounds which are amphoteric and have both a basic amino group and an acidic carboxyl group in their molecule have never been prepared so far and their features of pharmacological activities have not been reported.
Numbers of antihistaminic agents have been clinically developed and are used for the treatment of allergic dermatosis and rhinitis. However, they cannot be fully satisfactory from a safe point of view and problems are remained unsolved since they could cause adverse reactions such as sleepiness, sedation, hydrodipsia, mydriasis, palpitation, and arrhythmia because of their undesirable pharmacological activity of the inhibition of central nervous system, antiacetylcholinergic activity, activity against cardiovascular system or the like. Under these circumstances, clinical development of new antihistaminic agents and antiallergic agents have been desired which extensively eliminate these problems.